1. Field of the Invention
The present invention relates to a gas turbine installation which utilizes highly humidified air as the combustion use air thereof.
2. Conventional Art
For example, JP-B-1-31012 (1989) and JP-A-9-264158 (1997) disclose conventional art gas turbine installation making use of humidified air, in particular, a gas turbine cycle in which compressed air compressed by a compressor and heated liquid phase water being used as heat recovery medium are caused to be contacted at a humidification tower to obtain humidified air (mixture of air/steam) and cooled liquid phase water, with the obtained humidified air heat recovery of turbine exhaust gas is performed as well as by using the obtained cooled liquid phase water as heat recovery medium, heat recovery due to the turbine exhaust gas and intermediate cooling of the compressor are performed, and further, liquid phase water in an amount corresponding to that transferred as steam into the compressed air in the exchange tower (the humidification tower) is supplied to the exchange tower and into the liquid phase served for the heat recovery which is used as cooling medium downstream the intermediate cooler of the compressor which is performed by the cooled liquid phase water obtained at the exchange tower.
Further, JP-B-1-19053 (1989) discloses a gas turbine system in which without using the exchange tower (humidification tower) as disclosed in the above JP-B-1-31012 (1989) and JP-A-9-264158 (1997), with humidified air (mixture of mixed layers of compressed air/water/steam) which is obtained by injecting liquid phase water into outlet air of a compressor, heat recovery of turbine exhaust gas or the heat recovery of the turbine exhaust gas and intermediate cooling of the compressor are performed, and compressed air used for forming the humidified air is cooled in advance by a part of the humidified air.
Still further, JP-A-11-324710 (1999) discloses a humidification method of compressed air supplied from a compressor to a combustor in a gas turbine system in which an atomizer for atomizing water or steam to compressed air flowing through a regenerative heat exchanger is provided in the regenerative heat exchanger.
However, all of the above conventional arts do not sufficiently take into account a problem that scales (precipitates of impurities dissolved in water) caused when water droplets evaporate from a heat transfer surface of a heat exchanger stick on the heat transfer surface, therefore, the conventional art is possibly suffered to problems such as of lowering of heat transfer efficiency and increasing of flow passage pressure loss in a long time span.
When scales stick inside the regenerative heat exchanger, heat resistance of the heat transfer wall surfaces increases which causes to reduce overall heat transfer coefficient and heat transfer efficiency. Further, when scales stick on a narrow flow passage, it is possible that the flow passage is clogged. Still further, when working medium at both a low temperature side and a high temperature side is gas, the heat transfer efficiency thereof is poor in comparison with a case when the work medium is liquid, therefore, the size of a heat exchanger is generally like to be increased. For this reason, a plate-fin type regenerative heat exchanger which is also called as a compact heat exchanger and is constituted by very small flow passages is frequently used as a heat exchanger between gases. When gas containing water droplets are heated by making use of such plate-fin type regenerative heat exchanger, it is necessary to broaden space between heat transfer surfaces so as to avoid clogging, therefore, it was possible to cause problems of reducing heat transfer efficiency of the heat exchanger and increasing the size of the system. Still further, when such plate-fin type regenerative heat exchanger is used, it was required to thicken the plate thickness for countermeasuring erosion caused by liquid droplet collision which also increases the size of the installation.
An object of the present invention is to provide a compact gas turbine installation which suppresses generation of erosion and scales due to water droplets and shows a high efficiency and a high output.
A gas turbine installation of the present invention which achieves the above object includes a compressor which compresses air, a combustor which combusts the compressed air from the compressor and fuel, a turbine which is driven by combustion gas produced in the combustor, a regenerative heat exchanger which performs heat exchange between exhaust gas exhausted from the turbine and at least a part of the compressed air supplied to the combustor and a water spraying device which supplies water into intake air to the compressor or into the compressed air compressed by the compressor and is characterized in that the regenerative heat exchanger is constituted by connecting in series a plurality of heat exchangers having different heat transfer surface configurations.